Diabetes is a metabolic disease accompanied by increased blood glucose. It mainly comprises two types, i.e. Type I and Type II, with the latter being in the majority and accounting for 90% of patients with diabetes. Type II diabetes is mainly characterized by insulin resistance, in which uptake of glucose in liver, skeletal muscle and tissues such as adipose is decreased, leading to an increase of blood glucose level to result in high blood glucose. Cyclocarya paliurus is a deciduous tree of Juglandaceae family, and also named as Qing Qian plum or Jin Qian willow. It mainly grows in the southern mountain area in China at an altitude of 800 to 2000 meters which is dump and foggy. It is a monotypic plant unique to China. Cyclocarya paliurus comprises various active ingredients such as polysaccharides, flavonoids, triterpenoid saponins, and alkaloids. There have been researches showing significant effects such as reduction of blood glucose and blood lipid of the active ingredients. It has been found through researches that the extract of Cyclocarya paliurus plant can significantly enhance the tolerance ability of mice with diabetes induced by alloxan to glucose, has a strong inhibitory effect on the activity of α-glucosidase, can facilitate restoration of the structure and function of diseased islet, enhance the glucose tolerance of mice, and lower the fasting blood glucose level. Meanwhile, the extract of Cyclocarya paliurus plant also has obvious effects of improving blood lipid metabolism and enhancing antioxidant ability of the body. It can also inhibit the expression of FAS gene and protein in mice with hyperlipidemia. Therefore, there is a good prospect in developing the active ingredients of Cyclocarya paliurus plant as health food and medicament that lowers blood glucose level and blood lipid level, etc.
In recent years, the development of natural selenium-rich health products has attracted people's attention. Selenium is an important nutrient element essential for human body. It has physiological functions such as promotion of human body immunity, anti-oxidation, anti-aging, anti-cancer, and antagonization of heavy metal toxicity. Researches have shown that the occurrence and development of more than 40 types of diseases including Keshan disease, Kashin-Beck disease and diabetes are closely associated with selenium deficiency in human body. Currently, the standard of selenium daily intake amount by human body recommended by Chinese Nutrition Society is 50 to 250 μg, while the daily intake amount of selenium by adults is only 20 to 30 μg in China at present, which indicates a serious insufficiency of selenium intake. Problems such as low absorption rate in human body and high toxic side effects are present in inorganic selenium. Organic selenium is consistent with the natural form of selenium existing in human body and is easy to stay and accumulate in body, whereby the bioavailability is significantly increased with low toxic side effects. Therefore, it is necessary to develop a natural selenium-rich health product.
Currently, it is one of the simplest and most effective ways to obtain selenium-rich products by adding artificial selenium-rich fertilizers to render plants selenium-rich. However, selenium-rich fertilizers currently used in great amount are mainly produced from selenium ore powder or sodium selenite. Selenium ores always comprise many kinds of other heavy metals, and may make heavy metal concentration in soil and plants go beyond limits very easily. Sodium selenite is hard to be absorbed and transformed by plants. Large amount of unabsorbed sodium selenite will cause pollution to soil, water body and the surrounding environment. Furthermore, sodium selenite is toxic per se, and thus the residual sodium selenite on the surface of plants could cause damage to the health of human to some extent.
In view of the above, fertilizers used in cultivation of a selenium-rich plant in the prior art have disadvantages of high residue, poor absorption, and less environmental friendliness. Meanwhile, the current extraction and application of active ingredients in a selenium-rich plant have disadvantages of low absorption rate and high adverse reaction rate.
Accordingly, there is an urgent need for the skilled in the art to develop a selenium-rich organic fertilizer with high absorption rate, low residue and no harm to environment, and meanwhile to develop a method for extracting a selenium-rich plant with high absorption rate of active ingredients and less adverse reaction and the corresponding application thereof.